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While building an audience of trial customers compared to active customers, we are not able to see the subscription status. Why?
Kindly navigate to Settings > Setup > Field Mappings and check if the Subscription Status field is available. If not, you can add a custom field.
After which, you can search for 'Subscription status' under property while creating an Audience and pass the value as 'In Trial' for creating an audience for trial subscriptions. You can refer to the screenshot.